Device for Forming Dough Pieces

ABSTRACT

A method and device for forming dough in a U or annular shape includes a gripper carrier, at least one retaining jaw attached to the gripper carrier and first and second pivot carriers. The pivot carriers are each supported about a respective pivot axis in the gripper carrier and perform an opposite pivot motion. The second pivot carrier is supported by a shaft that extends into and engages the gripper carrier, such that a pivotal motion of the second pivot carrier engages the shaft with the gripper carrier to simultaneously pivot and lift the second pivot carrier so to lift one end of the dough piece in relation to another end of the dough piece. Shaping jaws are attached to the first and second pivot carriers and can be brought into contact with the respective dough piece on an opposite second side.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/697,840 filed Nov. 14, 2012, which is the National Stage ofInternational Application No. PCT/DE2011/000121 filed on Feb. 9, 2011,and claims priority to German Patent Application No. DE 10 2010 021149.4 filed May 21, 2010 and German Patent Application No. 10 2010 027622.7 filed Jul. 19, 2010. The contents of each of these applications ishereby incorporated by reference herein as if set forth in its entirety.

DESCRIPTION OF THE DISCLOSED EMBODIMENTS

The invention relates to a device and a method for forming dough piecesfrom a straight shape into a curved or annular shape.

From the state of the art different devices and methods are known forbringing dough pieces into a curved or annular shape. For this purposethe prepared straight dough pieces are fed into an appropriate device.The dough pieces are in particular croissant dough pieces, which arewound from triangular dough sheets. By means of the device the doughpieces are bent into a U-shaped form, which is particularlycharacteristic for croissants. Then the shaped dough pieces areforwarded to the subsequent processes and baked.

For continuous mass production, conveyor belts, on which the doughpieces are moved, are used in particular.

In one embodiment it is known from the state of the art tosimultaneously use said conveyor belt for shaping the dough pieces. Forthis purpose the conveyor belt develops from a flat appearance into alargely closed pipe and turns flat again towards the end of therespective conveyor belt. In this way, the dough piece is given itsannular shape by the conveyor belt while being transported along theconveyor belt.

The problem with this prior art is the fact that the dough piece mustnot tilt sideways or shift during the movement of the conveyor belt.This, however, can hardly be ensured during a running productionprocess. Therefore deficient products or malformed dough pieces occurregularly, which then have to be discarded.

For avoiding this problem, a further system is known from the prior art,in which two lateral conveyor belts are disposed vertically to thehorizontal conveyor belt, the two vertical belts effecting a pulling-inof the lateral ends of the dough pieces. It is also known to useinclined brushes which create an initial curved form of the dough pieceahead of the horizontally disposed conveyor belts. An example for thisembodiment is shown by document DE 100 34 177 B4. For the dough piecenot to be shifted from its position by the lateral vertical conveyorbelts, the dough piece can be centrally retained by a retaining element.Thus the lateral conveyor belts lead to a bending of the dough piecearound the central retaining element. In this way it is possible tobring dough pieces into a U-shaped form by means of a simple and quickprocess.

However, it is a complication in the implementation of this method thatthe dough piece has to be placed exactly in the middle of the conveyorbelt since this is the only way to ensure that the two lateral conveyorbelts bend the dough piece symmetrically. If, however, the previousprocess step cannot precisely place the dough piece on the conveyorbelt, it is necessary to bring the dough piece into the middle by meansof an additional device.

It is further disadvantageous in the aforementioned solution that it isnot possible to hereby create an annular shape, which is crucial inparticular due to the demand for a variation of the different doughshapes.

Therefore, it is the object of the present invention to provide a devicefor forming dough pieces, in which a U-shape and/or annular shape can beformed from the straight shape of the dough piece in a simple manner.

This object is attained by the solution of claim 1 according to theinvention. A method according to the invention for producing respectiveU-shaped and/or annular dough pieces is proposed in the main methodclaim.

Advantageous embodiments of the invention are the subject matter of thedependent claims.

The generic device serves the purpose of forming substantially straight,particularly wound, croissant dough pieces into a U-shape or annularshape. The form of a straight dough piece does not necessarilypresuppose an exact linear middle axis of the dough piece. Rather, it isan elongate dough piece which is formed predominantly straight. Thepurpose of a corresponding device is in particular the production ofwound croissant dough pieces. They are first formed in the known mannerfrom a wound triangular dough piece. The preferred embodiment ofcroissants is again U-shaped or annular.

According to the invention the device comprises a gripper carrier, towhich at least one rigid or movable retaining jaw is attached. Saidretaining jaw can be brought into contact with the dough piece on afirst side. The first side herein refers to a top view of the doughpiece, wherein the first side is a side of longitudinal extension of thedough piece. Further, two pivot carriers, which are each pivotablysupported about a pivot axis in the gripper carrier are attached to thegripper carrier. The pivot carriers perform an opposite pivot motion.The opposite pivot motion is realized on the basis of a largely parallelpivot axis. However, also a small angle between the pivot axes isinsignificant concerning the embodiment according to the invention.Depending on the relative movement of the pivot carriers in relation tothe gripper carrier a bearing between the pivot carrier and the grippercarrier is present. A rigid or movable shaping jaw is in turn attachedto the respective pivot carrier. The shaping jaws of the two pivotcarriers can now in turn be brought in contact with the dough piece onthe opposite second side. Herein it is initially insignificant if,regarding the middle axis of the dough peace, the retaining jaw and theshaping jaw are exactly opposed or offset to each other or oriented atan angle to one another. It is material that the retaining jaw and theshaping jaw are disposed on opposite sides and that the dough piece canbe clamped between the retaining jaw and the shaping jaws.

The solution according to the invention proposes that by means of thepivot motion of the shaping jaws attached to the pivot carrier and byclamping between the retaining jaw and the shaping jaws the shaping ofthe dough piece is made possible. Thus the device creates thepossibility to form U-shaped or annular dough pieces irrespective oftheir position by means of a retaining jaw and shaping jaws, as opposedto the state of the art. Therefore no other measures regarding theconveyor belt, such as lateral conveyor belts or belt guiding rods, arenecessary for creating a U-shape. Further advantages over prior artarise in the area of hygiene since the device according to the inventiononly retains a small degree of dirt, such as dough residue, and inaddition is easy to clean. Further, the gripper unit can be easilydisengaged or taken out of the work zone if required, for example whenan incorrectly rolled dough piece is fed into the device, in order topreclude any soiling from the start.

The device according to the invention is further advantageous regardingits required space within a production line. The highly compactstructure of the gripper unit enables a space saving integration of thedesired functionality of the positioning or bending of the dough piecesinto a production line.

The use of a pivot drive on the gripper unit is particularlyadvantageous herein, as is the use of a pivot gear. The pivot motion ofthe pivot carrier is initiated by the pivot drive. The connection of thetwo pivot carriers, which move in an opposite direction, is realized bymeans of the pivot gear.

Due to the use of a pivot drive with the connection of the two pivotcarriers by means of the pivot gear, it is possible in a simple mannerto realize the coupled motion of the opposite pivot carriers. Further,it is ensured by this solution that the dough piece is shapedsymmetrical. Herein it is possible to use a servo drive as a pivot driveas well as to realize the pivot motion by means of a linear drive, e.g.a pneumatic cylinder, via a crank rod.

Advantageously, the gripper unit further comprises a lifting device.Herein a pivot carrier and/or a shaping jaw are lifted in the directionof the pivot axis relative to the gripper and/or pivot carrier by thelifting device. The requirement of a possibly annular shape leads to theproblem of the colliding ends of the dough piece during the shapingprocess. In order to avoid this problem it is advantageous if one end ofthe dough piece can be lifted in relation to the other end. Thus it isparticularly advantageous if at the gripper unit a shaping jaw can belifted relative to the gripper carrier. Herein it is possible, forexample, to only lift the shaping jaw relative to the pivot carrier orto move the pivot carrier together with the shaping jaw relative to thegripper carrier.

The coupling of the pivot motion to the lifting motion is particularlyadvantageous for the realization of the lifting device. For this purposeit is possible to use a sliding block guide. The sliding block guide isdisposed between the gripper carrier and the second pivot carrier. As aresult of the pivot motion of the second pivot carrier the liftingmotion is simultaneously initiated by the sliding block guide. Thus itis ensured that the corresponding lifting motion is performed in anycase together with the pivot motion. For the realization of a slidingblock guide the person skilled in the art has different options at theirdisposal. It is possible, for example, to equip the shaft to which thepivot carrier is attached with an annular ascending groove and to have acorresponding pin with a rigid connection to the gripper carrier engageinto said groove. It is also possible to pull or push the shaft with thepivot carrier into a first direction by means of a spring force and toprovide therein an annular ascending surface with a rigid connection tothe shaft or to the gripper carrier, wherein on said surface a counterbearing with a rigid connection to the gripper carrier or to the shaftis supported. When the shaft rotates with the pivot carrier relative tothe gripper carrier, the corresponding axial motion is triggered by theascending surface.

From the processes it has been found problematic that the annular shapecannot be ensured in any case without further action after the forminghas been completed. Therefore it is advantageous if a press plunger isdisposed in the middle plane of the gripper unit and is movablesubstantially parallel to the pivot axes by means of a plunger drive.Herein the motion of the press plunger leads to a pressing of the endsof the dough piece lying on top of each other. Therefore the pressplunger is to be placed in a position on the gripper carrier in whichthe ends of the dough pieces in annular form lie on top of each other.The pressing of the ends of the dough pieces makes sure that after thegripper lets go of the dough piece the dough does not lose its annularshape. Hereby it is achieved that the dough piece largely retains itsannular form as desired after having been baked.

In this process the motion of the press plunger is coupled with themotion of the shaping jaws, such that the shaping jaws perform aretreating motion when the pressing process begins, i.e. the clampeddough pieces are released. This process ensures that the dough materialwhich is pushed outwards during the pressing of the ends of the doughpieces does not lead to an undesired deformation of the dough piece.Since the position is ensured already at the beginning of the pressingprocess and the shaping jaws are no longer needed for retaining thedough piece they can advantageously be detached from the dough pieceduring the pressing process.

Advantageously the gripper unit is embodied in such a manner that theshaping jaws can be moved relative to the retaining jaw. Thus it ispossible to realize the clamping of the dough piece without the doughpiece being improperly squeezed. The retaining motion of the shaping jawherein is preferably performed vertically to the middle axis of thedough piece. For this purpose it is possible to position the shaping jawso as to be turnable on the pivot carrier. Therefore the turn axis ofthis bearing between the shaping jaw and the pivot carrier is preferablyoriented parallel to the middle axis of the dough piece. Alternativelyit is possible to position the shaping jaw so as to be longitudinallyadjustable on the pivot carrier. For this purpose it is advantageous toorient the adjusting axis substantially vertically to the middle axis ofthe dough piece and vertically to the pivot axis.

For the embodiment of the gripper unit concerning the clamping of thedough piece different options are available. Herein it is possible inone embodiment to symmetrically position a retaining jaw in the middleplane of the gripper unit. The retaining jaw can be rigidly attached tothe gripper carrier or can alternatively be disposed so as to be heightadjustable in an axis parallel to the pivot axes. For forming the doughpieces the shaping jaws circle around the retaining jaw with the pivotmotion. By using a single central retaining jaw a particularly simplestructure of the gripper unit is realized.

However, it is particularly advantageous to rigidly attach a retainingjaw on each pivot carrier. For that reason two retaining jaws areprovided on the gripper carrier. Since the retaining jaws are connectedto the pivot carriers, they are consequently moved in opposite directionwith the pivot carrier.

By using a retaining jaw on each pivot carrier it is in particular madepossible to position the shaping jaw substantially opposite of theretaining jaw. Thus a secure clamping of the dough piece between therespective shaping jaw and the associated retaining jaw is madepossible. Further it is made possible by this embodiment to exert acertain pull on the dough piece and thus slightly elongate it.Considering the advantageous lifting motion of a pivot carrier, thispositioning of the retaining jaw opposite of the shaping jaw inparticularly leads to a secure guidance of the clamped end of the doughpiece during the lifting motion.

The form of the shaping jaw and the retaining jaw is secondary as astart. They can be formed with a circular cross section, as well asrounded or angular. However, it is particularly advantageous for thefixed retaining jaw if the contact surface with which the dough piececomes into contact has a circular or convex form in its cross section.In the direction of its longitudinal axis the fixed retaining jawpreferably has a cylindrical shape or an at least in parts tapering, inparticular conical shape. Due to the tapering of the fixed retaining jawa sticking of the dough piece during the detachment of the retaining jawby retracting the gripper unit is avoided.

It is advantageous for ensuring the shape of the dough piece and thetaking along of the respectively clamped ends of the dough piece andalso for avoiding a sticking to the retaining jaw and/or the shaping jawif the contact surface of the shaping jaw and/or the retaining jaw withwhich the dough piece comes into contact has a smooth surface.

It has proven to be particularly advantageous to have the retaining jawin its circumference turn conical towards its end. This is particularlyadvantageous when the retaining jaw is retracted from the dough piece.The conical shape leads to a relatively easy removal of the dough piecewithout any dough residue left behind on the retaining jaw when theretaining jaw is retracted in a vertical motion relative to the doughpiece. Thus there is no unwanted scraping motion or deformation of thedough piece when the gripper unit is vertically retracted. It is obviousthat in order to achieve this advantageous effect all that is necessaryis an inclination of the side of the retaining jaw which comes intocontact with the dough piece and that therefore the lateral or rearsurfaces or the circumference of the retaining jaw can be formedarbitrarily.

The application of the device according to the invention requires atleast the positioning of the gripper unit relative to the respectivedough piece that is to be formed. This can for example be done byexactly positioning the dough piece and lifting it. However, theapplication of a displacement unit on the device is advantageous,wherein by means of said displacement unit the gripper unit can at leastbe moved in a transport direction of a conveyor belt and in an axisvertical to the conveyor belt.

By using a displacement unit it is made possible in particular to formthe dough pieces on a running conveyor belt by means of the gripperunit. Herein the gripper unit can be lowered to the respective doughpiece and the dough piece can be formed while being transported. Thus,for forming the dough piece during the process, the only thing that isnecessary in addition to the device is the conveyor belt.

It is particularly advantageous to use a displacement unit which isfurther movable in a direction transverse to the conveyor belt andtherein, particularly for gripping, can be pivoted around a verticalaxis. Due to this embodiment it is possible in particular to grip and/orplace the dough piece in a desired position on the conveyor belt and toposition the gripper correspondingly above the respective dough piece.Thus the problem known from the state of the art of having to place thestraight dough piece exactly on the conveyor belt is overcome.

The form of the displacement unit herein is optional. Differentwell-known solutions are available to the skilled person for thispurpose. This can be, for example, a multi-axial robot or a portaldisplaceable in two axes with a supplemental pivot and lifting device.Also other solutions are obvious and not significant for the presentinvention.

Further it is particularly advantageous if the gripper unit can beexchangeably attached to the displacement unit by means of a toolchanging device. Thus the user has the option of respectively adjustinga production line to different types of dough pieces, in particular todough pieces of different sizes or forms, by a simple change betweendifferent gripper units. Additionally, by removing the gripper unit aneasy and thorough cleaning or maintenance of the components of thegripper unit can be made possible, in particular without shutting downthe production line.

According to a preferred embodiment, several gripper units, inparticular being positionable independently of each other, are attachedto the displacement unit. Thus, for example in a production line, anumber of dough pieces can be positioned and/or bent at once by thedifferent gripper units, such that the throughput of the unitcorrespondingly increases.

The implementation of the process for shaping the dough piece with acorresponding device is improved in particular if the device comprises aposition scanner with an analyzing unit. Herein the position of a doughpiece can be ascertained by the position scanner on the conveyor belt.The type of position scanner is optional, as long as it is made surethat the spatial position is registered from above looking down on theconveyor belt. It can be an imaging system, such as a camera, orultrasound sensors or the like. It is at least relevant that therespective position of the dough piece and therefore the deviation froma reference position is registered. Thus, the gripper unit can be placedin the correct position relative to the dough piece by the displacementunit. It is thus made possible to place the dough piece arbitrarily onthe conveyor belt, wherein the device automatically registers theposition of the dough piece and can put the gripper unit in acorresponding position above the dough piece.

It is further made possible by the embodiment according to the inventionwith an advantageous application of a displacement unit and a positionscanner to subsequently bring the dough piece into a target position byusing the gripper unit. This transport from a starting position of thedough piece to a target position can be done during the transport on theconveyor belt and herein during the shaping as well as before or afteror interrupting the shaping process.

The new solution therefore presents a method according to the inventionfor producing U-shaped or annular dough pieces from substantiallystraight, particularly wound, croissant dough pieces by using a gripperunit with at least one retaining jaw and two movable spaced shapingjaws, in particular a device according to the afore-mentionedembodiments, comprising the following steps:

First a transport of straight dough pieces to a forming station isperformed. How this transport is done is herein initially immaterial.

According to the invention the retaining jaw is lowered closely to adough piece underlay or the conveyor belt. This movement does notnecessarily have to be exactly vertical, but can also be a combinationof a motion vertical to the underlay and an approaching motion towardsthe dough piece. It is for example possible, to lower the retaining jawrelative to a gripper carrier or preferably the gripper unit with theretaining jaw. By then closing the gripper unit the necessary force forpositioning and forming the dough piece can be transferred in aform-fitting manner.

Further the two shaping jaws are moved until they come into contact withthe dough piece on the opposite side according to the invention. Due tothis motion of the shaping jaws to the dough piece a clamping of thedough piece between shaping jaw and retaining jaw is performed.

Finally, according to the invention, the shaping jaws are pivoted whileforming a curved or annular dough piece. By pivoting the shaping jawswhile taking along the ends of the dough piece a desired result isachieved.

Herein it is particularly advantageous if the first shaping jaw performsa pivot motion that is planar, curved, elliptical or circular forforming the dough piece. The second shaping jaw on the other handperforms a combined motion of a pivot motion that is symmetrical to thefirst shaping jaw over the middle plane and a lifting motion in thedirection of the pivot axis. Herein the second end of the dough piece isplaced above the first end of the dough piece at the termination of thepivot motion of the shaping jaws by means of the lifting motion of thesecond shaping jaw.

The application of the combined motions of the two shaping jaws leads tothe particularly advantageous shape of the respective dough pieces. Inthis way a corresponding annular shape is made possible in aparticularly simple manner.

The use of a press plunger is particularly advantageous, which pressestogether the overlapping ends of the dough piece. Herein the retractingmotion of the shaping jaws is triggered during or shortly after thecontact of the press plunger with the dough piece.

In particular, it is made sure by this embodiment that the dough pieceretains its annular shape after the shaping process is completed anddoes not flap open again afterwards or during the subsequent bakingprocess.

Further it is advantageous if prior to the lowering of the retaining jawthe position of the respectively arriving dough piece is scanned for itsposition on a conveyor belt. Herein the gripper unit is subsequentlyplaced above the respective dough piece.

Herein it is particularly advantageous if the dough piece can be broughtinto a target position by means of the gripper unit. This can happensimultaneously with the pivot motion of the shaping jaws or interruptingthe pivot motion.

In a special embodiment it is further possible that the position scannerrecognizes the middle tip of a wound croissant dough piece from itswinding. Herein the gripper unit is moved substantially vertically tothe middle axis of the dough piece relative to the conveyor belt beforeall jaws, i.e. the retaining jaws and the shaping jaws, come intocontact with the dough piece. By means of this motion, in particularduring contact of the retaining jaws to the dough piece, the dough piececan be put into a rolling motion due to its rolled shape. Herein it ispossible, as an improvement, to set the retaining jaws in a simultaneouscorresponding vertical motion. Due to this method step it is inparticular made sure that the shaping into a U-shape or annular shape ofwound croissant dough pieces always happens in the same manner and thattherefore no bending open or flapping open of the middle tip of theoriginally triangular dough sheet occurs.

In the following figures examples for the shaping process and fordevices according to the invention are illustrated.

FIG. 1 shows a course of the shaping process starting from a wound doughpiece to an annular dough piece;

FIG. 2 shows a first example of an embodiment of a device or gripperunit according to the invention;

FIG. 3 shows an alternative example of an embodiment of a device orgripper unit according to the invention;

FIGS. 4 a-4 c shows the sequence of shaping a wound dough piece with theposition of the shaping and retaining jaws;

FIGS. 5 a-5 b shows an alternative embodiment of a gripper unit with theshaping of the dough piece

FIG. 1 exemplarily shows the shaping of a croissant dough piece startingfrom a straight wound shape 36 to an annular shape 38. Herein the wounddough piece 36 is moved on a conveyor belt 02 into a transport direction03. In a preferred embodiment of the device or method according to theinvention, said dough piece 36 can be placed arbitrarily on the conveyorbelt 02. Subsequently, the shaping via a first curved shape of the doughpiece 37 a to an annular shape 37 b takes place. Herein the ends of theannular dough piece 37 b are disposed in an overlapping manner 39. Thenthe dough piece 38 is finished by adding an embossing 40 of theoverlapping ends 39 of the dough piece.

FIG. 2 is a sketch of a first example of an embodiment of a deviceaccording to the invention. The illustrated gripper unit 09 in itssimplest form can directly form the device 01 according to the inventionor is advantageously connected with a displacement unit not illustratedhere. The gripper unit 09 herein comprises as a start the grippercarrier 10. Below the gripper carrier 10 the two pivot carriers 16 and23 are illustrated. They are pivotably supported by means of a shaft inthe gripper carrier 10. The coupling of those two pivot carriers 16, 23is done by means of a pivot gear 13. Through this it is made sure thatthe two pivot carriers 16, 23 perform a corresponding opposite pivotmotion 19, 26 according to the invention. They are driven by a pivotdrive 12 which is exemplarily positioned above a shaft of a pivotcarrier 16 and is attached to the gripper carrier 10. Retaining jaws 17,24 are respectively rigidly connected to the pivot carriers 16, 23. Theshaping jaws 18, 25 according to the invention are positioned so as tobe movable relative to the pivot carrier 16, 23. In the illustratedexample the shaping jaws 18, 25 perform a linear contact motion 20, 27in the direction of the retaining jaws 17, 24. Thus the dough piecedisposed in between is clamped in by the contact motion 20, 27. Thepivot motion 19, 26 leads to a corresponding shaping of the dough pieceinto a corresponding U-shape or annular shape. For realizing the liftingmotion of the second pivot carrier it is proposed in this case that asliding block guide 29 with a groove in the shaft of the second pivotcarrier 23 with a pin on the gripper carrier 10 is used. When the pivotmotion 26 is performed the corresponding sliding block guide 29 leads tothe lifting motion 28 of the second pivot carrier 23 and thus to thelifting motion of the second retaining jaw 24 and of the shaping jaw 25.

FIG. 3 is a sketch of an alternative embodiment of a gripper unit 09according to the invention for a device. In contrast to the previouslydescribed solution this gripper unit 09 comprises a retaining jaw 11which is rigidly connected to the gripper unit 09. It is formedconically towards the end of the retaining jaw 11. This makes sure inparticular that no undesired scraping motion or deformation of the doughpiece takes place when the gripper unit 09 performs a verticalapproaching motion or a lifting motion away from the dough piece to beformed or being formed. In contrast to the previously described solutionthe shaping jaws 18, 25 are further turnably supported on the pivotcarriers 16, 23. Accordingly, the shaping jaws 18, 25 perform a turningmotion as a contact motion 20, 27. Also, as in the previously describedsolution, it is made sure that the shaping jaws 18, 25 are movedsubstantially vertically to the middle axis towards the dough piece.Further illustrated in this embodiment is the use of a press plunger 31.It is supported on the gripper carrier 10 and can perform acorresponding lifting motion 32. The position of the press plunger 31 isherein situated above the overlapping ends of an annularly formed doughpiece.

The following figures are sketches of particularly advantageousembodiments of the method according to the invention for forming a doughpiece 36. 37. 38 41. The forming process is flowing without taking onexplicit intermediate states. Thus, the illustrated steps are snapshotsof the process.

FIG. 4 a in a process step I illustrates how a dough piece 36arbitrarily placed on the conveyor belt 02 can be captured by a positionscanner in a scan area 34. Thereby the deviance from a referenceposition can be determined.

In the following process step II it is illustrated how the retainingjaws 17, 24 have been brought towards the dough piece 36 and howsubsequently the two shaping jaws 18, 25 are driven against the doughpiece by means of the contact motion 20, 27.

FIG. 4 b in process step III illustrates how the dough piece 37 a, nowclamped between the retaining jaws 17, 24 and the shaping jaws 18, 25,is deformed in the process by the pivot motion 19, 26. At the same timeit is possible to bring the croissant dough piece 37 a from the originalposition into a target position by means of an adjusting motion 07 andusing a displacement unit. All the while the process of forming thedough piece 37 a (step IV) can continue unhindered.

FIG. 4 c in process step V illustrates how the dough piece 37 b has beenformed into a ring by the retaining jaws 17, 24 and the shaping jaws 18,25. Due to the combined motion of the second retaining jaw 24 andshaping jaw 25 by the pivot motion 26 in combination with the liftingmotion 28 the overlapping 39 of the dough piece 37 b is made possible.

Then in process step VI the pressing of the overlapping dough piece ends39 by means of a press plunger 31 follows. In this motion the contactmotion 20, 27 of the shaping jaws 18, 25 is reversed as soon as theplunger touches the dough piece and the clamping of the dough piece 37 bis released. To support the removal of the dough from the press plunger31, air can temporarily be blown out of a nozzle at the front end of thepress plunger 31.

In an alternative embodiment FIG. 5 shows the forming by means of agripper unit 09 comprising a retaining jaw 11 and two spaced shapingjaws 18, 25. Herein the retaining jaw 11 is not pivoted along, butremains in the same position relative to the dough piece 36, 37, 41 andthe shaping jaws 18, 25 are guided in a circle around the retaining jaw11.

Further it is possible without any problems to use a fixed retaining jawas well as to provide in combination one movable retaining jaw per pivotcarrier.

1. A method for producing U-shaped or annular dough pieces fromsubstantially straight dough pieces using a gripper unit comprising atleast one retaining jaw and two movable spaced shaping jaws, said methodcomprising the following steps: transporting substantially straightdough pieces to a forming station; lowering the at least one retainingjaw toward a dough piece being transported, wherein lowering of theretaining jaw is controlled such that the dough piece is disposedbetween the retaining jaw and the shaping jaws; moving the shaping jawsuntil the shaping jaws come into contact with a side of the dough piece;pivoting at least one of the shaping jaws and the retaining jaw to format least one of a curved and an annular dough piece.
 2. The methodaccording to claim 1, in which, the two shaping jaws include a firstshaping jaw and a second shaping jaw, and the first shaping jaw performsat least one of a flat arc-, ellipse- or circle-like pivot motion,wherein the second shaping jaw simultaneously performs a combined motionincluding a first pivot motion symmetrical to the first shaping jaw overa middle plane, and a lifting motion in a direction of a pivot axis ofthe second shaping jaw pivot motion, wherein a second end of the doughpiece comes to a rest above a first end of the dough piece at atermination of the pivot movement of the shaping jaws.
 3. The methodaccording to claim 2, further comprising pressing together the secondend of the dough piece resting on the first end of the dough piece witha press plunger, wherein during or shortly after the contact of thepress plunger with the dough piece the shaping jaws return to a startingposition prior to engaging another dough piece.
 4. The method accordingto claim 1 further comprising determining a position of an arrivingdough piece on a conveyor belt and positioning the gripper unit abovethe arriving dough piece before lowering the retaining jaw.
 5. Themethod according to claim 1 in which the gripper unit is displaced withthe dough piece such that the dough piece is taken to a target positionsimultaneously with at least one of the pivot motion of the shaping jawsand interruption the pivot motion.